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Patented Apr. 7, 1931 UNITED STATES EUGENE DROUILLY, or PARIS, FRANCE, AssIGnon TO socintrii ANonYME TREFILERIES & LAMINOIRS DU HAVRE, ANGIENS ETABLISSEMENTS LAzARn WEILLER, sooni'rn COOPERATIVE DE Rumors 111 LA CANALISATION ELEcTRIQUE nEUNIs, or PARIS,

FRANCE, A FRENCH CORPORATION MANUFACTURE OF META I ILIO POWDERS 7 No Drawing. Application filed December 27, 1927, Serial No. 242,973, and in France November 16, 1927.

This invention relates to an electrolytic process for the manufacture of metallic powders, applicable to metals such as copper, zinc, cadmium, tin, lead, etc.

The electrolyte employed is a solution of a salt of the metal to be obtained, which metal is deposited on the cathode in a finelydivided non-compact or spongy form, and can subsequently be easily reduced to powder.

The use of the electrolyte in itself is not, of course, new, and the invention is characterized by the means which are used for carrying out the operation, the application of the means in question resulting in impalpable powders being obtained, of a fineness which has not hitherto been obtained.

On examining the action at the cathode during the electrolysis of a sulphuric acid solution of copper sulphate for instance, it will be seen that it is impossible to obtain non-compact deposits except by using current of considerable amperage. On examining such deposits under the microscope, which are obtained only with considerable concurrent generation of hydrogen at the cathode, it will be seen that in reality tangled crystals have been obtained, of such dimensions as to be incapable of producing impalpable powder.

If it is desired to obtain the metal in an extremely fine state of division, which is the object of the present invention, the applicant has discovered that it does not suifice to act only on the electric conditions of the deposit.

It is necessary to modify substantially the electrolyte bath itself as will be explained. In the course of the researches which have led to the new process, it has been found that the appearance of the deposit completely changes when certain suitably chosen organic products. are added to the metal salt. Such organic products are formed for instance when glucose is added to sulphuric acid and the said acid is heated. A carbonated product is thus prepared, which passes probably into colloidal solution. This product when added to the sulphate bath, ensures an extremely fine division of the cathode deposit and the generation of hydrogen at the cathode is reduced to almost zero, and it is PATENT; OFFICE. f M

not necessary in the application of this new 1 process to utilize current of great amperage.

Since the generation of hydrogen is reduced to practically zero, the deposit due to the current is practically the theoretical yield according to the Faradays law. The metal powder obtained is, moreover, finer, the greater the state of dispersion of the carbonated product and the nearer it is to a colloidal solution.

In place of the glucose treated with sulphuric acid, exceedingly finely divided sugar charcoal or any other variety of impalpable charcoal can be incorporated with the bath.

It seems that an electric transport of a finely divided inert powder takes place, which powder, being attracted towards the cathode, remains attached to it only just long enough to prevent the copper from settling in a continuous network.

The application of the phenomena hereinbefore referred to, renders it possible to obtain impalpable powders on the cathode, not only with copper salts, but also with the salts of zinc, cadmium, tin, lead, etc.

the fineness of which can reach a degree enabling it to pass through a No. 250 mesh, that is to say, through a sieve having 250 meshes per inch.

Claims:

1. In the electrolysis of metallic salt electrolytes to obtain metallic powders, the step which comprises electrolyzing a solution of a metallic salt containing carbonaceous material substantially in colloidal dispersion, only very small quantities of the dispersed substance being added in solution to produce the desired effect during several days, thereby giving a catalytic action.

2. In the electrolysis of copper sulphate solutions to obtain finely divided powdered copper metal, the step which comprises electrolyzing a solution of copper sulphate containing carbonaceous material substantially a metallic salt containing the carbonaceous,

In that way are obtained metal powders,

reaction product of glucose and sulphuric acid substantially in colloidal dispersion.

4:. In the electrolysis ofcopper sulphate solutiohs't'o obtain finely divided powdered copper metal, tlie step which comprises electrolyzing a solution of copper sulplia'te contwining the carbonaceous reaction product of glucose and sulphuric acidsubsta'ntially in colloidal dispersion? In testimony whereof I afiix my signature.

EUGENE DROUILLY. 

